/*=============================================================================
    Spirit v1.6.0
    Copyright (c) 2001-2003 Daniel Nuffer
    http://spirit.sourceforge.net/

    Permission to copy, use, modify, sell and distribute this software is
    granted provided this copyright notice appears in all copies. This
    software is provided "as is" without express or implied warranty, and
    with no claim as to its suitability for any purpose.
=============================================================================*/
#ifndef BOOST_SPIRIT_ESCAPE_CHAR_HPP
#define BOOST_SPIRIT_ESCAPE_CHAR_HPP

///////////////////////////////////////////////////////////////////////////////
#include <string>
#include <iterator>
#include <cctype>
#include <boost/limits.hpp>

#include "boost/spirit/utility/impl/escape_char.ipp"

///////////////////////////////////////////////////////////////////////////////
namespace boost { namespace spirit {

///////////////////////////////////////////////////////////////////////////////
//
//  escape_char_action class
//
//      Links an escape char parser with a user defined semantic action.
//      The semantic action may be a function or a functor. A function
//      should be compatible with the interface:
//
//          void f(CharT ch);
//
//      A functor should have a member operator() with a compatible signature
//      as above. The matching character is passed into the function/functor.
//      This is the default class that character parsers use when dealing with
//      the construct:
//
//          p[f]
//
//      where p is a parser and f is a function or functor.
//
///////////////////////////////////////////////////////////////////////////////
template <
    typename ParserT, typename ActionT,
    unsigned long Flags, typename CharT
>
struct escape_char_action
:   public unary<ParserT,
        parser<escape_char_action<ParserT, ActionT, Flags, CharT> > >
{
    typedef escape_char_action
        <ParserT, ActionT, Flags, CharT>        self_t;
    typedef action_parser_category              parser_category_t;
    typedef unary<ParserT, parser<self_t> >     base_t;

    template <typename ScannerT>
    struct result
    {
        typedef typename match_result<ScannerT, CharT>::type type;
    };

    escape_char_action()
    : base_t(ParserT()), actor(ActionT()) {}
    escape_char_action(ParserT const& p, ActionT const& a)
    : base_t(p), actor(a) {}

    template <typename ScannerT>
    typename parser_result<self_t, ScannerT>::type
    parse(ScannerT const& scan) const
    {
        return impl::escape_char_action_parse<Flags, CharT>::
            parse(scan, *this);
    }

    ActionT const& predicate() const { return actor; }

private:

    ActionT actor;
};

///////////////////////////////////////////////////////////////////////////////
//
//  escape_char_parser class
//
//      The escape_char_parser helps in conjunction with the escape_char_action
//      template class (see above) in parsing escaped characters. There are two
//      different variants of this parser: one for parsing C style escaped
//      characters and one for parsing LEX style escaped characters.
//
//      The C style escaped character parser is generated, when the template
//      parameter 'Flags' is equal to 'c_escapes' (a constant defined in the
//      file impl/escape_char.ipp). This parser recognizes all valid C escape
//      character sequences: '\t', '\b', '\f', '\n', '\r', '\"', '\'', '\\'
//      and the numeric style escapes '\120' (octal) and '\x2f' (hexadecimal)
//      and converts these to their character equivalent, for instance the
//      sequence of a backslash and a 'b' is parsed as the character '\b'.
//      All other escaped characters are rejected by this parser.
//
//      The LEX style escaped character parser is generated, when the template
//      parameter 'Flags' is equal to 'lex_escapes' (a constant defined in the
//      file impl/escape_char.ipp). This parser recognizes all the C style
//      escaped character sequences (as described above) and additionally
//      does not reject all other escape sequences. All not mentioned escape
//      sequences are converted by the parser to the plain character, for
//      instance '\a' will be parsed as 'a'.
//
//      All not escaped characters are parsed without modification.
//
///////////////////////////////////////////////////////////////////////////////

template <unsigned long Flags, typename CharT>
struct escape_char_action_parser_gen;

template <unsigned long Flags, typename CharT = char>
struct escape_char_parser :
    public parser<escape_char_parser<Flags, CharT> > {

    // only the values c_escapes and lex_escapes are valid for Flags
    BOOST_STATIC_ASSERT(Flags == c_escapes || Flags == lex_escapes);

    typedef escape_char_parser<Flags, CharT> self_t;
    typedef
        escape_char_action_parser_gen<Flags, CharT>
        action_parser_generator_t;

    template <typename ScannerT>
    struct result {

        typedef typename match_result<ScannerT, CharT>::type type;
    };

#if defined(__MWERKS__) && (__MWERKS__ <= 0x2407)
    escape_char_parser() {} // Don't take this line out CW7.2 will hate it!
#endif

    template <typename ActionT>
    escape_char_action<self_t, ActionT, Flags, CharT>
    operator[](ActionT const& actor) const
    {
        return escape_char_action<self_t, ActionT, Flags, CharT>(*this, actor);
    }

    template <typename ScannerT>
    typename parser_result<self_t, ScannerT>::type
    parse(ScannerT const &scan) const
    {
        return impl::escape_char_parse<CharT>::parse(scan, *this);
    }
};

template <unsigned long Flags, typename CharT>
struct escape_char_action_parser_gen {

    template <typename ParserT, typename ActionT>
    static escape_char_action<ParserT, ActionT, Flags, CharT>
    generate (ParserT const &p, ActionT const &actor)
    {
        typedef
            escape_char_action<ParserT, ActionT, Flags, CharT>
            action_parser_t;
        return action_parser_t(p, actor);
    }
};

///////////////////////////////////////////////////////////////////////////////
//
//  predefined escape_char_parser objects
//
//      These objects should be used for generating correct escaped character
//      parsers.
//
///////////////////////////////////////////////////////////////////////////////
const escape_char_parser<lex_escapes> lex_escape_ch_p =
    escape_char_parser<lex_escapes>();

const escape_char_parser<c_escapes> c_escape_ch_p =
    escape_char_parser<c_escapes>();

///////////////////////////////////////////////////////////////////////////////
}} // namespace boost::spirit

#endif
